The present invention relates to an apparatus for laminating plates. More particularly, the invention relates to an apparatus for laminating magnetic plates at aligned positions in the production of iron cores for transformers or the like.
In the conventional plate stacking apparatus for constructing the iron core of a transformer, for example, legs or yokes in the core are formed by lamination of pre-shaped magnetic plates. The magnetic plates must be aligned when laminated to provide a predetermined shape in the formed core, and special laminating apparatus or jigs are necessary. FIG. 10 shows a sectional view representing the basic arrangement of a conventional apparatus for such laminating of plates. In FIG. 10, a horizontal base 1 is provided with two upstanding cylindrical guide pins 2. Correspondingly, the laminated plates 3 are provided with guide holes 4 at predetermined positions. The predetermined positions are such that a section of a laminated body is formed to a predetermined shape when the guide pins 2 are inserted into the two guide holes 4 of each plate to laminate the plates. As the plates are laminated on the horizontal base 1, two workers 5 hold respective edges of one plate 3 to position the guide holes 4 upon the guide pins 2 so that the guide pins 2 are received in the respective guide holes 4 and so that each plate 3 falls on the base 1 while it is guided by guide pins 2. In accordance with such a procedure, the plates 3 are laminated on the horizontal base 1 in an order to develop the predetermined shape of the core or core part. The assembly 30 formed by a predetermined number of the plates is lifted from the guide pins 2 as a structure of a core leg or yoke while being oriented in a horizontal attitude. Moreover, such lamination of the plates 3 may be performed by a machine or with the use of tools instead of the manual operation described. A basic feature of the above-described conventional lamination is that the plates are presented perpendicular to the guide pins in order.
However, the conventional lamination of the plates has the following problems. As shown in FIG. 11, when a plate is being guided by pins 2, the plate 3 may become inclined with respect to the pins so as to bind and stop along the lengths of the pins. In large size transformers, the length of an iron core leg or part may be as long as 5 meters, for example. Ordinarily, with a plate of such length, the falling speed throughout the length of the plate may not be constant. Moreover, it is difficult to maintain the horizontal orientation of the plate as it is lowered on the pins and, quite frequently, the plate may hang up and stop on the pins. When this occurs, the plate 3 should be pulled up from the pins and repositioned thereon, or the plate 3 should be adjusted so as to fall smoothly along the pins. As a result, the laminating procedure requires excessive time and labor.
Further, when a plurality of plates are laminated and the guide pins are pulled out from the laminated assembly, a large frictional resistance is generated between the guide holes and the guide pins, so that the guide pins are difficult to pull out. Accordingly, the plates may not be laminated to form a thick layered assembly at one time. As a result, a small number of the plates are laminated and pulled from the pins as relatively thin, subassemblies which are further laminated to each other to provide the predetermined thickness and shape of the layered body. This process is troublesome.